The objective of this research project is to study the effects of infused prostaglandin precursors on pulmonary gas exchange in unanesthetized adult rabbits. These studies will be conducted in rabbits following recovery from placement of jugular venous and carotid arterial catheters. Arterial and venous levels of PG E, PG F2 alpha-Metabolite and 6-keto F1 alpha, arterial PO2 and PCO2, end-expired PO2 and PCO2, and triglyceride levels will be serially measured during and following infusions in Intralipid, arachidonic acid, and control infusions of saline. The results obtained in rabbits with normal lung function will be compared to results obtained in rabbits with lung damage induced by oleic acid. The results of these studies in rabbits with normal and damaged lungs will also be compared to results obtained in the rabbits pretreated with indomethacin. Additional studies will be performed in rabbits with induced neutropenia and thrombocytopenia. The results of this study will provide important physiological and clinical information regarding the mechanism and significance of pulmonary alterations occurring secondary to the infusion of prostaglandin precursors, and will relate the pulmonary alterations occurring to changes in circulating levels of vasodilating and vasoconstricting prostaglandins.